Thermostat



C. PEEBLES THERMOSTAT Aug. 13, 1935.

Filed July 19, 1954 Patented Aug. 13, 1935 UNITED STATES PATENT OFFICE THERMOSTAT 4 Claims.

My invention relates generally to improvements in thermostats and the main object is to provide an improved, self-regulating and efhcient form .of thermostat suitable for any use wherein heat from a flame or the like is utilized to controleither the intensity .of that flame or other device. As an example the thermostat may be used with a suitable arrangement of levers to automatically close the gas cock or valve of a gas stove and shut off the gas should the gas flame be accidentally extinguished or blown out.

Another object is to provide a thermostat of this kind comprising a stand having a shaft journaled through near its intended upper side and a pair of thermostat carrier arms secured on said shaft and extended radially outward therefrom, there being guide ears or extensions on the stand below the carrier arms and having angularly extended guide or cam slots, 2. bimetallic thermostat strip coiled in a spiral coil and secured at its inner end to the outer ends of the carrier arms and extended at its free end down between the guide ears, and guide rollers journaled and attached to said free end of the thermostat strip and playing in the said guide slots.

Another object is to provide a thermostat device of the above kind which may be connected in several ways to the device or devices to be controlled, the connection being made either to the shaft carrying the thermostat carrier arms or to a connecting element afiixed to the free end of the thermostat strip, the action of the shaft as heat is applied to the thermostat being rotary and the action of the connecting element on the strip being reoiprocative.

With these and other objects in view the invention resides in the novel construction and ar rangement of parts as hereinafter fully set forth and claimed, reference being had to the accompanying drawing wherein:

Figure 1 is a side view of my thermostat, the parts being shown in normal or at rest position.

Figure 2 is a side View showing the position of the parts when heat is applied to the thermostat.

Figure 3 is a plan view as shown in Figure 1.

Figure 4 is an end view.

Figure 5 is a detached fragmental perspective View of the connecting element and guide rollers.

Figure 6 is a side view of a modified form of guide roller assembly and a fragment of the thermostat strip.

Figure '7 is a side view, reduced in scale, showing the position of the thermostat relative to a gas stove burner and a part of an operating mechanism for controlling the gas cocks of the stove.

Referring now with more particularity to the rawing, my invention comprises a stand .I made up in an inverted U-shaped or bridge-like form 5 and including spaced vertical and parallel sides 2 having outwardly turned and perforated mounting feet 3 at their lower ends and joined at their upper ends by the top or bight 4. A pivot or drive shaft 5 is journaled horizontally 10 through apertures 6 in said sides 2 adjacent the bight l and a pair of elongated, spaced and paral el thermostat carrier arms 7 are rigidly affixed at on end 8 to said shaft, there being a spacer collar s and washers I 8 disposed on the 5 shaft as shown. In their normal position as will be hereinafter more clearly pointed out these carrier arms I extend substantially horizontally outward from the shaft 5 (Figure l) and extend toward what is hereinafter termed, for c0nven-- 20 ience in description, the rear of the structure. At their outer free ends ii the arms 7 are rigidly joined by a short stub shaft or pin l2.

The stand sides 2 have rearwardly and slightly upwardly extended guide ears or extensions I3 formed on their rear sides near the mounting feet 3 and said ears have similarly inclined rear- Wardly and upwardly extended guide or cam slots It in lateral alignment and terminating at their rearmost ends in notches or wells 55 cut in their lower edges as shown. A thermostat strip made up in conventional lei-metallic form of two metal strips having unequal coeflicients of expansion is formed into a spiral coil l6 which is secured at its inner end ii to the stub shaft 12 .and the coil is disposed between the carrier arms I. The outer free end l8 of the thermostat coil extends down between the ears i3 and a connecting element and roller carrier designated generally at [9 is affixed to this end of the thermostat. This con- 4 necting element is made up of a strip of steel or other metal bent to provide a tang 2t riveted, welded or otherwise secured to the end l8 0f the thermostat strip and having marginal ears 2i turned down and apertured at 22 to take a guide roller axle 23 which is extended through and outwardly at each end from the ears. Guide rollers 24 are journaled in this axle Y23 and are .so disposed and dimensioned that they may play freely in the guide slots M- as shown. The free end I8 of the thermostat coil is thus anchored in the guide slots and the coil i6 is so tensioned and made that normally it tends to draw the rollers 24 up into the notches l5 and hold the carrier arms 1 elevated to the substantially horizontal position shown in Figure 1 and hereinbefore mentioned. Outwardly or forwardly of the tang 2!] the connecting element is is bent forwardly and then upwardly forming a forwardly disposed connecting tab or end having an aperture 26.

As one example of the use and operation of the device attention is invited to Figure 7 wherein the thermostat is shown as mounted on any suitable form of base A adjacent the burner B of a conventional gas stove. An extra burner hole C is bored so that the flame therefrom will strike the thermostat coil It when in its elevated position. A mechanism of any suitable form is provided for controlling the gas cocks (not shown) of the stove and said mechanism may include a lever D pivoted at E on a plate F and arranged in operation to be swung upward or downward by action of the thermostat. For this purpose an operating finger G is secured by nuts H to the tab 25 and extends therefrom and is pivoted at I to an offset J on the lever D.

Now the flame from the extra burner hole 0 will play directly on the thermostat coil Iii and will cause said coil to expand or uncoil (the position of the bi-metallic strips being proper) whereupon the free end 38 will lift the rollers 2d from the notches i5 and cause them to glide down along the slots M to the position shown in Figure 2. The connecting element l9 thus is carried forwardly and upwardly and the finger G correspondingly moved will swing the lever D upward on its pivot E as will be clearly understood. The thermostat coil 16 and the carrier arms I are at the same time swung downward (partially rotating the shaft 5) and the coil it drops away from the flame at hole 0 until the coil automatically adjusts itself to the heat from the burner. If the flame is suddenly lowered to its lowest practical point the coil 16 slowly contracts and elevates itself to again reach a stable point. Now should the flame be entirely extinguished accidentally the coil will further rise and the rollers 2 will drop back into the notches l5, the lever D being at the same time lowered finally to its starting point at which it will through suitable mechanism close the gas cocks. There is readily sufficient nicety of adjustment to accomplish this movement from low heat to no heat and the drop afforded by the rollers 26 falling into the notches i5 is sufficient to bring about this action. An important advantage lies in the fact that the thermostat will not under any conditions become overheated since it automatically moves further away from the flame as the heat increases.

The thermostat may, of course, be used to control other devices either through a similar connection to the tab 25" or through geared or crank connection to the shaft 5. A gear 2'! is shown as secured on this shaft and also a counter balance weight 28 which may be adjusted to any position to aid in the rotation of the shaft by the thermostat. The shaft 5 may, of course, be any practical length. Where the drive is only from the shaft 5 the guide rollers 24 may be mounted on a small U-shaped bracket 29 secured to the thermostat end 78 instead of the element 99, this bracket having ears 2 la carrying the axle 23 as clearly shown. It is thought that further detail as to the operacured at one end to the shaft and extended radially therefrom, and a thermostat coil mounted between the outer ends of the said arms and secured at its inner end thereto, guide ears extended out from the stand beneath the said arms, and having angularly extended guide slots with notches at their outer ends, and guide rollers carried by the free end of the thermostat coil and mounted for travel in the said guide slots.

2. In a device of the kind described, an inverted U-shaped stand including spaced sides, a pivot shaft journaled through the sides of the stand, a pair of spaced carrier arms secured on the pivot shaft within the stand and extended outward therefrom, guide ears formed on one edge of the stand sides and extended beneath the said carrier arms, the said ears having outwardly and. upwardly inclined guide slots having notches in their lower edge at their outer ends, a spiral thermostat coil mounted between the carrier arms and secured at its inner end thereto, the free end of the thermostat coil being extended down between the guide ears, and rollers journaled on said free end of the thermostat coil and arranged to travel in said guide slots and to normally rest in the said notches.

3. In a device of the kind described, an inverted U-shaped stand including spaced sides, a pivot shaft journaledthrough the sides of the stand, a pair of spaced carrier arms secured on the pivot shaft within the stand and extended outward therefrom, guide ears formed on one edge of the stand sides and extended beneath the said carrier arms, the said ears having outwardly and upwardly inclined guide slots having notches in their lower edge at their outer ends, a spiral thermostat coil mounted between the carrier arms and secured at its inner end theretmthe free end of the thermostat coil being extended down between the guide ears, and rollers journaled on said free end of thetherrnostat coil and arranged to travel in said guide slots and to normally rest in the said notches, a connecting element attached to the free end of the thermostat coil for movement thereby, a gear secured on the said pivot shaft for rotation thereby, and a counterweight secured on the pivot shaft.

4. In a device of the kind described, a stand, a shaft journaled in the stand, arms secured to and radially extended from the stand, a thermostat coil mounted at the outer ends of the arms and attached at its inner end thereto, guide ears extended from the frame and having guide slots, and guide means carried by the outer end of the thermostat coil and adapted to travel in said slots.

CHARLES PEEBLES. 

